How to Install Vinyl Replacement Windows

If you have basic tools and skills you can install your own vinyl replacement windows and save hundreds of dollars in installation charges—for each window.

By the DIY experts of We do everything by our own hands Magazine

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Time

One day

Complexity

Simple

Cost

$100 – $500

Install your own vinyl replacement windows

Vinyl replacement window

Vinyl replacement windows come mounted in a new jamb, and are simply tilted into the old frame and fastened in place.

Close up

Top frame cutaway. The inside stop molding helps hold the new window in place.

Close up

Vinyl trim and caulk seal the gap at the bottom of the new window. The window fits against the existing stool on the inside.

Learning how to install replacement windows looks complicated, but actually requires only basic tools and skill—despite the high prices charged by some window replacement companies.

However, before deciding to tackle the how to install replacement windows job yourself, check the condition of your existing window frames. If they’re rotten or badly out of square, the whole unit, including the frame, may need replacing. This is a much bigger and more complicated job than installing a vinyl window insert and may require a pro.

If the frames are sound, the next step is to measure the interior width and height of each window frame side to side and top to sill. Double-check these measurements to ensure their accuracy so you don’t end up with a window that doesn’t fit. In most cases, the old frame dimensions will match a standard- size vinyl window.

Use these measurements to order the windows from a lumberyard or home center. The price will vary depending on the manufacturer and the features you request. Order windows with insulated glass (two layers). Then consider whether to copy the style (single or multiple glass panes) of the old windows or to change it.

The windows install from the inside. Give yourself at least half a day to install the first unit. Once you’ve learned the steps, the second installation will go much faster.

Here’s a summary of the steps for replacing windows:

Remove and save the inside stop. It’ll be reused in the same place.

Remove the old lower window sash (not shown).

Pull out the parting stop (see top frame detail). Don’t worry about breaking it; you won’t be reusing it.

Remove the old top sash (not shown).

Either remove the sash liners and springs or open the sash pockets and pull out the weights. Remove the sash cord pulleys and stuff the weight pockets with fiberglass insulation.

Push the new vinyl unit into place tight against the outside stop and drive the mounting screws in the sides.

Caulk around the outside and install the vinyl trim pieces.

Reinstall the old inside stop.

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

Caulk gun

Cordless drill

Hammer

Hearing protection

Level

Pry bar

Safety glasses

Tape measure

Utility knife

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.